This invention relates in general to strengthening wood-frame construction, and in particular, to a method of strengthening wood-frame construction and increase its resistance to high wind, earthquake or blast loadings by applying strips of fiber reinforced polymers to the panels. A very common wood frame construction method uses wood or steel studs or wood or steel framing with plywood or Oriented Strand Board (OSB) sheathing panels or stucco sheathing. The framing/sheathing combination forms shear walls and horizontal diaphragms which resist horizontal and vertical loads applied to the structure. This form of construction is used in the majority of single family homes in the United States, as well as a significant portion of multi-family, commercial and industrial facilities.
While the system has generally performed well, the economic losses in the United States due to natural disasters, such as hurricanes, earthquakes and tornadoes, have been mounting. The economic losses caused by these natural disasters in the United States has averaged about $1 billion/week in recent years. Most of these losses are due to hurricanes (80%) and earthquakes (10%). For example, loss of roof sheathing under hurricane winds has often been attributed to improper fastening of the sheathing to the framing, such as by the use of larger nail spacing than allowed by code, nails missing the support framing members, or over-driven nails. Loss of sheathing in hurricanes weakens the roof structure and can lead to roof failures. The water damage resulting from a loss of roof sheathing or roof failures has been a major contributor to economic losses in hurricanes. Surveys also show that a significant portion of the damage resulting from hurricanes or earthquakes occurs in nonstructural parts of the home due to excessive deformation or movements of the structure. The cost to repair nonstructural damage often makes it necessary to rebuild the structure rather than to repair it.
While the knowledge to mitigate hurricane and earthquake damage exists today, building code provisions are often misunderstood by builders, and compliance with regulations is difficult to enforce because of the difficulty of inspecting in the field. As a result, surveys show that a significant portion of the damage to homes and property caused by natural disasters is due to lack of conformance to codes. Improper connections between walls at building comers, such as non-overlapping top plates or improper or missing hold-downs to tie the shear walls to the foundations, are further examples of poor construction practices that are difficult to inspect.
Therefore, there is a need for a simple, easy-to-inspect, inexpensive construction method to strengthen and stiffen conventional construction for improved performance against hurricane and earthquake damage. The construction method should increase the strength and ductility of wood buildings and reduce the deformation of the buildings to limit damage to non-structural members.
The above objects as well as other objects not specifically enumerated are achieved by a building construction configuration comprising an assemblage of wood sheathing panels positioned adjacent one another to form a panel assembly having elongated joints between adjacent panels, and reinforcement strips of fiber reinforced polymer material bonded to the panels. The reinforcement strips cover an area that is within the range of from about 5 to about 50 percent of the surface area of the panels.
In another embodiment of the invention, there is provided a building construction configuration comprising an assemblage of wood sheathing roof panels positioned adjacent one another to form a building roof having elongated joints between adjacent panels, and reinforcement strips of fiber reinforced polymer material bonded to the panels. The reinforcement strips cover at least 20 percent of the joints, thereby bonding together substantially all of the panels in the building roof.
In another embodiment of the invention, there is provided a building construction configuration comprising an assemblage of wood sheathing roof panels positioned adjacent one another to form a building roof having elongated joints between adjacent panels, and reinforcement strips of fiber reinforced polymer material bonded to the panels. The reinforcement strips are concentrated at the ridge, eave and edge areas of the roof.
In another embodiment of the invention, there is provided a building construction configuration comprising an assemblage of wood sheathing roof panels positioned adjacent one another to form a building roof, and an assemblage of wood sheathing shear wall panels positioned adjacent one another to form a building wall. A joint is formed between the roof panels and the shear wall panels, and reinforcement strips of fiber reinforced polymer material are bonded to at least some of the roof panels and at least some of the shear wall panels.
In another embodiment of the invention, there is provided a building construction configuration comprising an assemblage of shear wood sheathing wall panels positioned adjacent one another to form a first building wall, and an assemblage of shear wood sheathing wall panels positioned adjacent one another to form a second building wall, where a joint is formed between the first building wall and the second building wall. Reinforcement strips of fiber reinforced polymer material bonded to at least some of the shear wall panels in the first building wall and at least some of the shear wall panels in the second building wall.
In another embodiment of the invention, there is provided a method of constructing a building comprising applying wood sheathing panels to a framework to form a building shell, bonding reinforcement strips of fiber reinforced polymer material to the wood sheathing panels to bond at least some of the wood sheathing panels to each other, and covering the building shell with a finished exterior.